Recovery Frequency of Phytophthora ramorum and Other Phytophthora spp. in the Soil Profile of Ornamental Retail Nurseries

Susceptibility of Selected Ericaceous Ornamental Host Species to Phytophthora ramorum

Phytophthora ramorum (S. Werres, A.W.A.M. de Cock & W.A. Man in’t Veld) sp. nov. causes sudden oak death (SOD), which is a canker disease of certain oak species that has killed thousands of trees in California since 1995 (13,28) and has moved northward into southwestern Oregon (17). In Europe, P. ramorum is described by Werres et al. (34) as causing a dieback of Rhododendron and Viburnum spp. b...

Phytophthora ramorum

Phytophthora ramorum in North America

Two apparently unlinked events marked the beginning of one of the most devastating forest diseases known to man in recent times: Sudden Oak Death (SOD). In the mid 1990s, while a novel species of Phytophthora was being isolated from mildly diseased Rhododendron and Viburnum plants in German and Belgian nurseries, the first reports of inexplicable death of tanoaks (Notholithocarpus densiflorus) ...

Recovery of Phytophthora ramorum Following Exposure to Temperature Extremes

Phytophthora ramorum Werres, De Cock & Man in ‘t Veld, a recent introduction into the United States, has proven to be a threat to hardwood forests on the west coast, specifically tanoak (Lithocarpus densiflorus (Hook & Arn.) Rehder) and Quercus spp. (34). This pathogen has a broad host range which is ever-expanding and includes understory plants and commonly grown nursery plants (19,25). Some n...

Genotyping Phytophthora ramorum Isolates From Nurseries in the United States Using PCR- RFLP and Microsatellite Analyses

The risk of introducing the important plant pathogen Phytophthora ramorum outside of its present natural range is of extreme concern; however, the detection of P. ramorum in U.S. nurseries is increasing. The USDA has confirmed the presence of P. ramorum in nurseries in 21 states that received plants from an infested, southern California nursery and others. This nursery produces approximately 15...